<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <h2>当前计数：{{counter}}</h2>
        <button @click="add">+</button>
        <button @click="sub">-</button>

        <!-- <button v-on:click="counter++">+</button>
        <button @click="counter--">-</button> -->
    </div>
    <script src="../js/vue.js"></script>
    <script>
        const app = new Vue({
            el: '#app',
            data: {
                counter:0,
               
            },
            beforeCreate:function(){
                console.log("beforeCreate")
            },
            // created里面做网络请求
            // 生命周期函数 生命周期钩子（hook）
            created:function(){
                console.log("created");
            },
            mounted:function(){
                console.log("mounted");
            },

            methods:{
                add(){
                    console.log('add被执行');
                    this.counter++
                },
                sub:function(){
                    console.log('sub被执行');
                    this.counter-- 
                }
                

            }
        })
    </script>
</body>
</html>